The present invention relates to an apparatus for separating out light materials from mineral raw materials, especially from sand and gravel, and includes a charging means for the raw material, an inner chamber, as a coarse sand chamber, for separating out the coarse sand, and with an outer chamber, as a fine sand chamber, that serves for the sorting out of the fine sand pursuant to the fluidized bed process, with this outer chamber communicating with the coarse sand chamber via an overflow embodied as an inclined surface, as well as an overflow for the light materials associated with the outer chamber, whereby the charging means includes a charging tube that ends centrally above an impingement body that is centrally disposed in the inner chamber and leaves free an outer annular gap.
An apparatus of this general type is described in EP 0 508 335 A2; by means of the configuration described therein, the known apparatus intends to avoid the pretreatment of the raw material charge, so that it is possible to directly supply the raw material coming from the extraction or the screening into the separating apparatus. However, in doing so large quantities of water in the charge can have a disadvantageous effect, since such large quantities of water cause great hydraulic stress of the coarse sand chamber and therefore either material that is too coarse is transported into the fine sand chamber or fine sand substituents are carried along beyond the fine sand chamber into the light material overflow.
It is therefore an object of the present invention to improve an apparatus having the aforementioned features such that larger quantities of water that pass, even in an abrupt manner, into the separating apparatus with the material charge can be managed without having an adverse effect upon the separation success of the apparatus.